The present invention relates to dispensers for aerosols or other pressurized products, and more particularly to a pressure resistant plastic bottle for dispensing an aerosol or other comparably pressurized product.
The term “aerosol” will be understood herein to encompass both aerosols, literally, and other liquid or flowable products that can be dispensed from pressurized containers in a manner comparable to aerosolized products. Such products include but are not limited to foamed or gel preparations or to liquid products delivered in a non-aerosol stream.
Pressurized containers for dispensing aerosols are well known in the art, and are typically constructed of metal in order to withstand the inherent internal pressure of aerosols. However, it is desirable to provide a plastic container capable of withstanding the internal pressures generated by an aerosol because plastic has many advantages over metal. Some of these advantages include the ease and economy of manufacture, and aesthetic appeal to an end user.
Despite the desirability of using plastic containers, there are some disadvantages to utilizing plastic materials. For example, it is desirable to avoid plastic containers that have abrupt changes in configuration. The areas of such abrupt changes are stress concentration points which are inherently weak. Another disadvantage is that when the container is subject to internal pressure, certain features of a plastic container may deform. Depending on the wall thickness of the container, the internal volume may change between 3 to 5%. As a result of such stress, slight bulging and/or skewing of the container may occur causing the container to become unsightly, and depending on the location of the deformation the container could become unstable and may not rest properly on a table or other flat surface. It is thus necessary to provide a container design or shape which, when made of a plastic material, can most effectively resist the internal pressures generated by an aerosol without rupturing or becoming unduly distorted. Also, if internal volume changes do occur, then it is desirable that they occur uniformly so that such deformation can be accounted for in the design of the container. Thus, if deformation is known to be uniform, then the container can be designed to accommodate such uniform deformation with the result that the container will be less likely to leak its contents and/or rupture.